The present invention relates to detecting a leak in a boiler of an electrically conductive liquid. More specifically, but without limitation thereto, the present invention relates to detecting a leak in a molten lithium boiler and transmitting an alarm signal to a remote location.
Molten lithium boilers are typically used in Rankine cycle engines to power torpedoes such as the MK50. To protect surrounding components from boiler temperatures of up to 2,000 degrees Fahrenheit, the boiler may be insulated with a heat-resistant fabric made from fibers of materials such as silicon dioxide quartz and alumina-boria-silica ceramic. An example of a commercially available heat-resistant fabric is available from JPS Glass Fabrics under the name ASTROQUARTZ. A stainless steel casing may cover the boiler and the insulation to hold the heat resistant fabric in place and to reflect radiant heat away from surrounding components. Leaks in lithium boilers occur frequently, and are consistently observed in the boiler end walls and at the entry points of the boiler injectors.
During the recovery of torpedoes after a test run, there is a hazard to recovery personnel from venting toxic gases if a leak has occurred in the lithium boiler. However, a lithium boiler leak is not discoverable until after the torpedo is recovered. Consequently a leak must be assumed and special equipment and handling procedures must be used to avoid exposing personnel to danger from possible exposure to venting toxic gases during the recovery of a torpedo. Determining whether a leak has occurred during a test before recovering a torpedo would facilitate recovery procedures in instances where no leak has occurred and extra precautions are unnecessary. A need therefore exists for a means of determining whether a boiler leak has occurred before the recovery of a spent torpedo and in other applications where molten metal boilers may present a hazard to personnel if a leak occurs. The present invention is directed to these needs and may provide further related advantages.